Ultrafiltration regulation by differential weighing
First Claim
1. An apparatus for regulating ultrafiltration during hemodialysis comprising:
- a hemodialyzer for the dialysis and ultrafiltration of blood including inlet and outlet blood ports, an inlet dialysate port for the entry of fresh dialysate and an outlet dialysate port for the exit of spent dialysate including ultrafiltrate added to the dialysate in the hemodialyzer;
a differential weighing receptacle having an inlet chamber and an outlet chamber, said inlet chamber having a fluid inlet opening for receiving fresh dialysate, and a fluid outlet opening in fluid communication with the inlet dialysate port of said hemodialyzer for the delivery of fresh dialysate to said hemodialyzer, said outlet chamber having a fluid inlet opening in fluid communication with the outlet dialysate port of said hemodialyzer for receiving spent dialysate including any added ultrafiltrate therefrom, and a fluid outlet opening for the draining of dialysate from said outlet chamber;
means for concurrently allowing the inlet chamber to fill with fresh dialysate while spent dialysate is emptied from the outlet chamber and to alternate functions in cyclic fashion; and
weighing means associated with said receptacle for weighing a pre-selected amount of fresh dialysate which fills said inlet chamber when said outlet chamber is substantially empty, and for weighing the amount of spent dialysate and ultrafiltrate associated therewith which fills said outlet chamber when said inlet chamber is substantially empty for determining the difference in weights between fresh dialysate weighed in the inlet chamber and spent dialysate, including ultrafiltrate, weighed in the outlet chamber to thereby monitor and control the amount and rate of ultrafiltrate removed from blood in said hemodialyzer.
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Accused Products
Abstract
Hemodialysis ultrafiltration apparatus comprises a hemodialyzer, a supply line for supplying fresh dialysate to the hemodialyzer. A drain line is provided for removing spent dialysate from the hemodialyzer. The dialyzer is adapted to be connected to a patient so that the patient'"'"'s blood may be supplied to and removed from the hemodialyzer. A weighing mechanism allows a fixed amount of fresh dialysate, by weight, to flow through the hemodialyzer. Spent dialysate emerging from the hemodialyzer is then weighed by the weighing device to determine the weight differential therebetween to monitor and control the amount and rate of ultrafiltrate removed from blood in the hemodialyzer.
A method of hemodialytic ultrafiltration is carried out substantially in accordance with the above-described apparatus.
91 Citations
14 Claims
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1. An apparatus for regulating ultrafiltration during hemodialysis comprising:
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a hemodialyzer for the dialysis and ultrafiltration of blood including inlet and outlet blood ports, an inlet dialysate port for the entry of fresh dialysate and an outlet dialysate port for the exit of spent dialysate including ultrafiltrate added to the dialysate in the hemodialyzer; a differential weighing receptacle having an inlet chamber and an outlet chamber, said inlet chamber having a fluid inlet opening for receiving fresh dialysate, and a fluid outlet opening in fluid communication with the inlet dialysate port of said hemodialyzer for the delivery of fresh dialysate to said hemodialyzer, said outlet chamber having a fluid inlet opening in fluid communication with the outlet dialysate port of said hemodialyzer for receiving spent dialysate including any added ultrafiltrate therefrom, and a fluid outlet opening for the draining of dialysate from said outlet chamber; means for concurrently allowing the inlet chamber to fill with fresh dialysate while spent dialysate is emptied from the outlet chamber and to alternate functions in cyclic fashion; and weighing means associated with said receptacle for weighing a pre-selected amount of fresh dialysate which fills said inlet chamber when said outlet chamber is substantially empty, and for weighing the amount of spent dialysate and ultrafiltrate associated therewith which fills said outlet chamber when said inlet chamber is substantially empty for determining the difference in weights between fresh dialysate weighed in the inlet chamber and spent dialysate, including ultrafiltrate, weighed in the outlet chamber to thereby monitor and control the amount and rate of ultrafiltrate removed from blood in said hemodialyzer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Hemodialysis ultrafiltration apparatus comprising:
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hemodialysis means; means for supplying fresh dialysate to and for removing spent dialysate, including ultrafiltrate, from said hemodialysis means; means for supplying and removing blood from said hemodialysis means; and differential weighing receptacle means for allowing a first amount of fresh dialysate, by weight, to flow into said hemodialysis means and for weighing a second amount of spent dialysate flowing out of said hemodialysis means corresponding thereto, said means further comprising means for determining from the weight differential between the first and second amounts of dialysate the amount and rate of ultrafiltrate removed from the blood in said hemodialysis means.
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8. A method for regulating ultrafiltration during hemodialysis comprising:
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supplying blood to and removing blood from a hemodialyzer; supplying fresh dialysate to an inlet chamber of a differential weighing receptacle and concurrently removing spent dialysate from an outlet chamber of said receptacle; weighing said fresh dialysate in said receptacle, and, upon reaching a pre-selected weight level when said outlet chamber is substantially empty, preventing the further flow of fresh dialysate into said inlet chamber; allowing only said fixed amount of fresh dialysate, by weight, to flow through said hemodialyzer; collecting spent dialysate including ultrafiltrate, emerging from said hemodialyzer into said outlet chamber and weighing it over a time period not greater than the time period for said fixed amount of dialysate to flow through said hemodialyzer; determining the weight differential between said fixed amount of fresh dialysate and said spent dialysate to monitor and control the amount and rate of ultrafiltrate removed from blood in the hemodialyzer. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of hemodialytic ultrafiltration comprising:
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supplying fresh dialysate to and removing spent dialysate, including ultrafiltrate, from hemodialysis means; supplying and removing blood from said hemodialysis means; periodically allowing a known amount of fresh dialysate, by weight, to flow into said hemodialysis means; periodically weighing with a differential weighing receptacle means the amount of spent dialysate associated with said known amount which flows out of said hemodialysis means; and determining the weight differential between the known amount of fresh dialysate and the associated amount of spent dialysate so as to allow the amount and rate of ultrafiltrate removed from the blood in said hemodialysis means to be monitored and controlled.
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Specification